1. Field of the Invention
The present invention relates to a composition or a method for preventing treating, improving and/or ameliorating a disease associated with β-amyloid in brain which is at least one selected from dementia, memory impairment and memory, by using.
2. Description of the Related Art
Generally, dementia is a symptom showing remarkably decreased brain functions such as the abilities of memory, thinking, understanding, calculating, learning, language, and judgment, in which the brain normal cell is damaged due to various reasons.
In particular, Alzheimer's disease is an important disease of senile dementia, and is mainly caused by the accumulation of β-amyloid in the brain and its neurotoxicity (Probst A. et al., Brain Pathol., 1:229-239, 1991). It has been reported that β-amyloid makes the protein plaque in brain, thereby causing the occurrence of Alzheimer's disease (Breimer L H, et al. Nature, 326: 749-750, 1987).
The β-amyloid is prepared by reacting amyloid precursor protein (APP) with β-secretase (BACE1) and gamma-secretase sequentially (Vassa and Citron, Neuron 27, 419-422, 2000). β-amyloid is largely classified into two types; Aβ40 of 40 amino acids and Aβ42 of 42 amino acids. β-amyloid is predominantly Aβ40 but a relatively small amount of Aβ42 makes plaque formation easily and thus is considered as a factor causing the disease (Selkoe, Science 298: 789-891, 2002).
The representative drugs for treating dementia which are commercially available are tacrine (Cognex, 1994) and donepezil (Aricept, 1996) used after U.S. FDA approval. The mechanism of drugs to prevent and treat the dementia has been known for increasing the concentration of the neurotransmitter acetylcholine by inhibiting the activity of acetylcholinesterase (AChE) degrading the acetylcholine which plays a central role in central nervous transmit system. However, the tacrine is expensive and has serious hepatotoxicity. Donepezil does not have hepatotoxicity, but causes various side-effects such as nausea, anorexia, diarrhea, and etc. by stimulating the parasympathetic nerve.
Therefore, a new drug for treating dementia which can treat the causes of the disease and does not have the side-effects is still needed and has been researched actively. As a part of the research, there is an effort to continuously develop a drug for inhibiting the formation of β-amyloid.
Monsonia sp. belongs to the family, Geraniaceae and is used for improving the indigestion and intestinal bleeding, etc. in southern Africa (Burkill, The useful plants of west tropical Africa, Vol. 2, The Royal Botanic Gardens Kew, 1994). Monsonia angustifolia grows naturally in Africa, especially the whole of South Africa. Monsonia angustifolia has various uses for treating such as headache, anthrax, blackwater fever, diarrhea, ophthalmia, snakebite, hemorrhoids, stomach ulcer, indigestion, and varicose veins in Africa (Roberts, Indigenous healing plants, Southern Book Publishers, 1990, pp. 81-82). It is also recorded that Monsonia angustifolia is used for liver disorder in african folk remedy (Ichikawa, The database of traditional plant utilization in Africa Center for African area studies, Kyoto University, http://130.54.103.36/aflora.nsf), but there is no published research on it. Other than a patent disclosing the use of a plant extract which includes Monsonia angustifolia for treating erectile dysfunction and improving libido (Fouche, WO 2007138531), there is no scientific report on the medicinal use of Monsonia angustifolia. 